


Brothers In Arms

by skerb



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), Angst, Angst with a Happy Ending, Blood and Gore, Canon-Typical Violence, Fights, Fontcest, Forced Servitude, Implied/Referenced Torture, Incestuous feelings, M/M, Mental Health Issues, Murder, Revenge, Underfell Asgore Dreemurr, Underfell Papyrus (Undertale), Underfell Papyrus/Underfell Sans (Undertale), Underfell Sans (Undertale), regicide ideation
Language: English
Status: Completed
Published: 2019-11-28
Updated: 2019-11-30
Packaged: 2021-02-26 04:40:14
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 8,699
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21597778
Author URL: https://archiveofourown.org/users/skerb/pseuds/skerb
Summary: Set in Underfell. After pushing Sans into a pocket of space to save his life, Papyrus is forced into servitude under the mad king's rule, believing his brother to be dead after an act of defiance.Sans continues on by himself, blinded and alone and seething in his own rage. He plans regicide for his life's burden, unknowing whom the Bloodhound is at Asgore's back and call.
Relationships: Fellcest, Papyrus/Sans (Undertale)
Comments: 50
Kudos: 126





	1. Chapter 1

**Author's Note:**

  * For [nilchance](https://archiveofourown.org/users/nilchance/gifts).
  * Inspired by [every me and every you](https://archiveofourown.org/works/15227427) by [nilchance](https://archiveofourown.org/users/nilchance/pseuds/nilchance). 



> **  
> **  
> Content warning(s) in end notes  
>  Based on nilchance's Blind!Red AU " **[let's take this to the grave](https://archiveofourown.org/works/15227427/chapters/51285841)** " but also kind of a "separation AU" but I had to make it more sad because of course I did. These events take place after Red defies Fellgore and what Edge endures in the aftermath. Both are referred to their canon names.

**Notes for the Chapter:**

> content warning(s) in end notes

Papyrus isn’t sure how he’s managed it nor how he expects Sans to survive on the other side, but he gives his brother a final push into the pocket of space between them. Sans is gone in an instant. He inhales the sharp smell of blood and iron, the smoke and ochre that naturally hangs around his brother. Papyrus knows he’s doomed. There’s no need for Sans to be brought down with him when Asgore has his way.

Sans is gone and all that remains is a spray and smear of blood on the floor, a stain on Papyrus’ hands as he collects himself. Dust taints the blood and fear sweat that collects between his joints, trapping the urge to ball them into hard fists and lash out.

He needs to collect himself. He needs to work this to his advantage. Asgore is insane and oh, how Papyrus _loathes_ him, but there’s still pockets of clarity that make his cunning far more unpredictable than what Papyrus can brace himself for.

He can feel the king’s looming presence behind him, thick as a wound and just as penetrating. Papyrus swallows when he can feel the blistering weight behind him, knowing that _this is it._

_This is the end._

* * *

He knows that his brother is as good as dead. It doesn’t stop the fact that his soul twists up every time his name is uttered by the king, and Papyrus must bite back the ensuing insults and vulgarities if he plans to live longer than he already has.

Papyrus lies in wait for just the right moment to strike, but it’s much too soon.

Somehow, the Angel has deemed fit to taunt instead of help him, and Papyrus internally fights with himself every day that passes to not outright mock his ideology just to satisfy his lust for vengeance.

The king had expressed… _disappointment_ in Papyrus’ involvement regarding Sans’ escape. By some laughable move of the cosmos, Asgore spared him, though not without subjecting Papyrus to torture. He’d survived it, though barely. It must’ve amused the insane king, proving his prowess under such heinous treatment. It’d taken weeks to recover, and even now, Papyrus sports a slight limp on days where he’s stretched thin.

Sans is dead. If he’s not, he wasn’t alive for very long. He’s had no opportunity to go search for Sans, not with his injuries and not with the royal guard breathing down his neck everywhere he goes. It’s not that Papyrus thinks his brother weak, no, that was never the case, but his brother had been gravely injured. And while he’d managed to buy him time, his wounds were mortal and without proper treatment would fester and consume Sans. Papyrus doesn’t regret his decision to not allow Asgore the killing blow to his only remaining family.

~~_His lover._ ~~

…

To further teach him a lesson in fidelity, he’s been ordered under Asgore’s rule to be his personal guardsman, in charge of protecting the king. It took some… _persuasion,_ and Papyrus mentally flinches at the memory of bone splintering. While normally being assigned to such aristocracy would make his station the most coveted of all, it isolated him, making the insane king his only companionship. As such, Papyrus’ already haunted nights became increasingly long as every sound in Asgore’s castle echoed in its dusty halls.

Perhaps there’s a shard of hope somewhere in the husk of Papyrus’ soul that he’ll exact justice on the fiendish sovereign. It’s a dull beat, reminding him of years earlier, when Sans’ soul had been strained so much to begin to crack and Fall. It bought them a few extra years together and Papyrus wouldn’t trade anything in the world to take it back. But he misses his brother with enough heartache to fall a legion.

He buries it inside, amongst memories of his brother he dares not breathe out loud. He keeps them for himself, treasured in his heart like a locket that’s been welded shut. He berates himself for being pathetic some days when he’s strong. Other days, Papyrus can’t help but grieve.

* * *

It’s a long process to heal when the wound festers from the reason why Sans is dead in the first place. Though it’s no easy process, Papyrus steels himself over time. His answers to orders are curt, without refusal most days. Sometimes, his station as protector to the tyrant levies him a silver tongue to reason out Asgore’s insane jurisdictions. Things have been manic without a proper Judge.

Asgore does not go out. He stays in his keep, feeding portraits of his dead family with a store of rotted food so old even the magic preserving it is starting to wane. Papyrus amuses the king, though Asgore is more bound to unsettle his guard dog than to confide in him.

The other guards stationed around the castle do not trust him any more than they trust the king. Papyrus is fine with that; it allows him to sink into the role all the better. It’s easier to convince the king of his supposed loyalty, though Papyrus would love for nothing more in the world than to sweep the head clear off Asgore’s shoulders.

~~_What he wants is his brother back._ ~~

It’s a wonder he’s alive. Papyrus begrudges it for as long as he clings to the hope that one day he’ll bring Asgore to justice. For all the pain they’ve all suffered under his deteriorating sanity, his vile laws and the manipulative way he rules as though his decisions don’t outweigh the consequences outside of his hall.

Asgore has made a ruling in recent years. If Papyrus’ memory serves him, it’s been four, perhaps five years since he pushed his brother out of the hall of the mountain king. He scored the date into one of his proximal phalanges, but years of doing the king’s dirty deeds has eroded and scarred his bones over time. He’s discarded his name, as he has no use for it anymore. The only one that said it with any real purpose is long gone, and he doesn’t want to taint the memory.

The Edge of Vengeance has a dramatic flair that he’s come to grow fond of in that sharp, stabbing way of his. It almost feels like warmth when he can never feel those hands again.

* * *

Papyrus is a shell of his former self when he sees the monster before them. They aren’t anyone particularly special; a hairless monster with reddened eyes swathed in clay-brown robes from the western districts between Hotland and the capital. They’d blathered on for nearly six minutes, with Asgore lounging egregiously into his throne with a massive claw held to his temple.

Simpering makes the king testy.

The full bearance of his majesty is like a thick black fog, a prickle and miasma of LV hanging in the air and the beast inside that seeks to claim the free kill in front of them. Papyrus doesn’t look, but he knows the leer he feels against his body when Asgore looks at him, burning him on the spot.

The tyrant then turns to Papyrus as though he’s his consultant, like Papyrus’ words hold any weight in the hall of the mad king. Papyrus stands straight, not proud, but he’s been acting for so long that the mask is familiar enough. His crimson eye lights slide to the side, hiding his contempt for his ruler with a brusk salute.

“Tell me, my esteemed guardsman,” Asgore says, his voice low and so deep that it unpleasantly reverberates through Papyrus’ marrow. The way in which the king speaks is distant and wondrous. It’s one of the days where he’s a little lucid and more like the shadow of a man he once was. “This one. Why are they here.”

The enquiry bears a lot of weight. Papyrus knows for a fact that while they have shady business practises, it’s no darker than anyone else’s. He recalls the refusal to give up the last of the provisions they’ve stowed away, and it must’ve come back to the intelligence services; white fingers behind the king’s paranoia. The thing is with Asgore’s ruling is that the laws are always changing, and Papyrus feels more like a magistrate these days than a guard dog.

Gritting his teeth (and remembering Sans scolding him for doing so in his youth), Papyrus forces himself to adjust the mask of obedience and speaks; “Your ruling, Sire, by all accounts should no monster refuse free supply to the Crown and its sundries.”

Asgore considers it. Papyrus could’ve seen the vague echo of recognition in the king’s bloodshot eyes, if he’d only looked. Instead, he stays perilously quiet, as though calculating the moves of a madman who dropped the serum in an asylum long ago.

“I see.” His tone is so low that it’s enough to bear down on the two other monsters present. It forces a whimper from the merchant on the floor before him. Papyrus detects the flare of irritation at his side and braces himself.

It’d been happening a lot lately.

“Then, my dear guardsman,” as the king speaks, Papyrus forces himself not to grind his teeth again; he feels increasingly ill with the continued pet names, “I have no use for such traitors. Kill them.”

It’s as though the entire universe homes in on the moment. Papyrus remains silent, though his mind races through every possible excuse not to follow through. It’s one of the days where his LV burns particularly bright, so it feels easy to give in. Easy, but not necessarily justified, as he doesn’t have the possession that plagued his brother.

Asgore seems to forget this quite frequently. Perhaps Papyrus hesitates a little too long, since the king adds, his voice impossibly lower, “That’s an order, Lord Edge.”

Papyrus’ teeth set in a jagged line and he can’t prevent himself from going forward. He doesn’t have what Sans had, the determination to refuse orders from the king when it was convenient for him. He doesn’t have the Judge, thick in his marrow to suddenly clamp over his soul and puppet him with unearthly obedience.

What he does have is the sense to obey when he knows his life is in the mad king’s claws, as much a vice around him as it is around the kingdom. If he refuses, it’s taken as mercy, as insubordination and treason. He wouldn’t spare the merchant’s life and he’d only be jeopardising his own.

Papyrus can’t risk it. Not for a stranger. Not when he’s sacrificed so much. He wants to see that stupid crown skid across the tiles soaked in blood, but he resists.

What he does do is send a look so livid that it could melt the snow beams in the western lands, and Asgore…

Asgore only looks bored. Nonetheless broken, but he holds Papyrus’ gaze steady.

There’s enough hesitation that there’s another flare of recognition in Asgore’s eyes. The king never speaks of that day too often anymore, but Papyrus’ hesitance must be bringing it to focus. Papyrus is gambling too much on the old monster’s frail mental stability.

Self-defense is one thing, but he’s never considered killing anyone snivelling at Asgore’s feet. Papyrus makes a disgusted noise low in his false throat and constructs a bone attack, sharp as a spear and blood red like his magic. Negligibly, he hurls it at the merchant, and it finds its mark, interrupting their scramble to offer something for sale.

The king seems pleased. Papyrus doesn’t rise in tiers, but he’s close enough that the LV biting at his brain hisses and screams from within his soul. It morphs his perception for a moment, the colours dullening around him, coating everything crimson. He grips his fists in tight leather gloves so hard it bites into the grooves of his joints.

The world is dark.

* * *

The king’s requests only get worse from then on. For one reason or another, the kingdom needs to be cleansed. There are traitors everywhere. Papyrus finds himself more an executioner rather than a magistrate over recent years, and he’s put up a fight once or twice, enough for him to learn not to press the king’s patience. Papyrus’ legs ache from the healing salve, but he stands still at the monarch’s side.

The kingdom is revolting under Asgore’s rule. The population numbers are dwindling, mostly in that the people fear their children will be next. It filters through the ranks that people have given up the prospect of rearing progeny, and turf wars and executions are making the monster populace shrink.

The people detest ‘Edge’, the king’s right hand man, whose killer eyes are sharp enough to cut diamond from bedrock. The insane king’s bloodhound. The unfeeling executioner.

He supposed he should’ve seen it coming. Security has stepped up and Papyrus cares little for the pain he suffers. He still waits for the opening Asgore will give him, still yearns to taste justice for his brother’s death. It’s been almost twelve years. There’s no whisper of Sans in the streets when he goes out. No assurances that he’s causing havoc in Snowdin, no bar fights in New Home.

What’s dead is dust. There are no such thing as corpses to mourn. He has nothing left of his brother but the memories in his heart.

It’s all a distant memory until he sees a flash of gold on someone too far away to tell. Instantly, Papyrus smells a faint echo of old cigarettes and whiskey. He wonders if his sight is failing him, too many strikes to the head, or the crack over his right eye is starting to deteriorate his vision. The figure far away seems just as bad. Papyrus catches what they look like and his soul suddenly thumps _hard_ in his chest. Scars over each of their eyes _(orbits),_ musty, dirty and scuffed bones, thick and old brown leather coat with a handsewn emblem on the shoulder.

A thick collar that hangs from their neck sporting an array of spikes so unfathomably sharp it’s wonder they haven’t impaled themself.

Papyrus recognises his handiwork when he sees it.

_Sans._

He’s constantly watched, he knows this, has always hated it, but his entire being yearns towards his brother with everything he has. His feet don’t move. He’s still, trying to take in Sans’ appearance from a distance. If he does anything to reveal Sans’ location, he’s as good as dead. And with his brother’s reappearance, all the grief and love and _guilt_ comes rushing back to him like air after being nowhere but in cloudy waters.

For the first time, Papyrus feels a kindle of longing and mentally beats it back.

_He’s alive._

He doesn’t allow it to show. He’s still weary on the outside, a hardened warrior with nothing to lose, the insane king’s bloodhound. When he retreats to his meagre quarters, Papyrus ends up staring up at the ceiling in the dark for hours, but for a different reason entirely. His soul feels lighter. He feels _hopeful._ Papyrus feels that after so long, all that needless waiting and suffering and deaths, that Sans is alive and adaptative in the streets of the capital.

He doesn’t cry, but his soul feels overfull. There’s a traitorous burn behind his eyes like someone’s lit a gas fire in his skull, but Papyrus manages to blink back the tears. Even in his room, he isn’t safe. Not until the king is dead.

For once he sleeps the sleep of someone who has dreams, and they don’t shift to nightmares. Papyrus dreams of having Sans pressed against him in bed, his scent on his bones, his warmth under his fingers, the taste of his mouth. Even as he sleeps, his soul reacts with a flutter of hope.

_He’ll get to see him again._

**Notes for the Chapter:**

> **Content warning(s):** reference to past eye trauma, violence, thoughts of regicide, incestuous feelings, grief, mentions of torture, forced confinement and servitude, murder.


	2. Chapter 2

**Notes for the Chapter:**

> content warning(s) in end notes

When Sans lands in a heap on the other side of the Underground, he’s still wheezing, screaming, still in blind pain and shock. He tastes the blood in his mouth, fights the bile in his false throat. The vertigo and blindness wash over him in a nauseating wave, and all he knows is that Papyrus isn’t with him.

~~_Forgive me, Sans._ ~~

He upturns the waste magic, choking on the remnants as quietly as he’s able to. It settles on him with astounding clarity that he has no backup. He has no brother, who used his bullshit anti-gravity space manipulation to force him into…

…wherever this was.

Sans doesn’t know where he is, but he knows immediately to shut the fuck up before someone pulls a cheap shot on him. He’s shaking and cold, his face burning with pain and an oncoming fever, but he blindly stumbles into the bushes. Someone’s nearby. Probably heard him losing it. He’s pissed and distraught, and nothing is going to make his day better.

Fear of death in unknown surroundings is a sobering thing, apparently. Sans tests his magic and while it protests from being stretched so thin, he manages a quick spurt through the void to hide up in a tree, about four clicks south of their town. It’s cold, but the piney boughs offer shelter when he knows his disobedience cost him their home, their lives-

Papyrus’ life.

Sans’ soul doesn’t not give in to that pathetic squeeze it does from time to time. The magic in his orbits is shattered, the Judge broken and silenced. For once, he’s alone in his head and Sans isn’t sure how to process it. He’s never had complete silence before. He would’ve been able to handle it if he could hear his brother’s voice, but he can’t. That idiot separated them for his goddamn hero/martyr complex and for what? To die pointlessly at the hands of the king?

Sans hates it. His anger riles up inside of him, bubbling up the pain when another wash of vertigo hits him. He’s nauseous and on top of it all, he has no way of figuring out where other people are. He’s a sitting duck.

All he knows is that he’s alone in the world, in pain, and the only reason he continues to live is out of spite from then on.

* * *

The world is eerie in its silence, but it’s filled with those who are alive. Sans has managed so far, using his powers of the void to quickly waltz in and out of hiding until his orbits are healed. His sight doesn’t come back, and what’s more is whatever emotion he feels is trapped inside of him. He doesn’t react when he shortcuts into the attic of their home and listens for anything, finding only more silence. He ignores the way his soul squeezes, how his false throat traps a hoarse laugh. It’s not a cry. He’s learned he can’t produce the tears required even through healing.

There are no allies. He does a sweep of Snowdin from the crawlspace of their house, but he doesn’t risk others homing in on his location for long. He discovers that he can utilise blue magic to trace people, using glancing Checks to see who they are. It’s a static state, like tracing his fingers over familiar letters raised on a dais, but it’s unused and clumsy.

The first few years are a miracle he’s even alive. His first encounters result in a lot of EXP gain, and people learn to avoid him. Any guards that come after him don’t return, but his LV isn’t so high that it attracts attention. Instead, he’s exiled, which is a good fucking joke to someone who can show up and disappear in the blink of an eye.

But Sans starves for the most part, though he grows reckless in his confidence once he starts thievery. He hasn’t held a gold coin for months and he walks in the open. The entire space between him and anyone that might cross his path is as black as the expanse between stars, and it grows familiar to him.

Does he regret his actions? There’s a yes and no answer to that loaded question. If Sans gave it any amount of consideration, he would’ve conceded to the fact that it wasn’t worth the life of his brother. His brashness had cost him more than anything in the world, and there was nothing he valued more than his family.

On good days, his mind eats at him, blaming him, _you did this. It’s your fault he’s dead._ Papyrus would’ve come back to him if he wasn’t.

He keeps the collar, touches it like a bruise, like a reminder. The collar is not unlike a wedding band, and to hell with the notion that he’d discard it just because his brother is no more. The magic and intent fused into the leather and metal is familiar and bright, and on bad days, Sans hides and breaks down while he clutches it in his fists. Papyrus would’ve come back if he was alive, but if he was dead the magic would’ve waned by now. He would’ve scolded Sans not to stress the leather.

He keeps it on and cherishes it, holds the feeling of Papyrus in his soul. Infrequently, when the LV’s making his life a living hell, he thinks he hears his brother’s voice, mocking in that not-unfamiliar way of his that he’s growing sentimental. In order to fend off the memory, Sans tells it to fuck off. The memory is bittersweet, but he’s alone.

* * *

Days when his LV rides him are different now. The first time he was subjected to its usual flares came without the echoes of the Judge, whom would add its nattering and mental causality to the mix; _murderer, shame, guilt._ Any variety of excuses that he was responsible for the reason why Papyrus grew up too fast. Any amount of (true) accusations that he’d messed up their lives for good.

Sans rides it out alone, the silence in his head deafening. It’s an adjustment, one he can’t handle alone. His first few flareups aren’t what he’s used to, and it’s like he’s eight again, the bite of new LV burning in his marrow. Only this time, he doesn’t have his brother to worry after him.

He shakes his head to rid the memory of a gentler time. Of a weaker time. He’s gotta get through this.

He’s grown fond of trees; they provide good cover, and rarely does anyone look ceiling-ward. No one can hear his shaky breaths nor the way he trembles, as though Sans is flying apart without a tether to the world.

He’s never been so secluded in his life.

* * *

Sans becomes reckless as he masters his own body again. Learning to live without sight when the world looks at you like a bit of free EXP is stressful, to say the least. It’s the single most motivator beyond self-preservation that keeps his ass alive in the years that follow. He walks in public, his grin sharp, his bones alight with fury.

No one fucks with him. No one understands how he walks around.

He makes his way from Snowdin to Waterfall, but keeps hidden in the marshes like a ghost ship. The twisting paths give him trouble, and the trail of dust he leaves behind makes the waters run red. It’s been six years since Papyrus hurled him to the opposite side of the Underground, and Sans has never forgotten it. There’s no reason to live for any longer than he has to without his brother.

All that drives him is the fact he’s sworn to tear Asgore apart or die trying.

Hotland’s easier to navigate with the heat, though its terrain makes it more perilous than the marshes before it. At least his body is attuned to heat, dodging it to avoid severe burns or worse. Sans bitterly clouts the fact he’s used a shortcut every chance he got for any reason at all in the past; navigating Hotland is surprisingly easy.

The smells are different, stronger. He can tell them apart from the rock formations to the fire monsters that hang outside of his boundaries, as though they’re tempting fate. Once or twice Sans allows them to get close enough and spills their dust as a warning to others.

Before his world changed forever, he was at LV 5. It wasn’t too high, maybe the ‘usual’ for his temperament and situation. He’s at LV 8 now and it bites into his psyche like vipers, distracting him on bad days to the point where he has to hide. It follows him like a bloody, dusty shadow, invisible hands enclosing over his throat.

A touch to the collar and it makes it all bearable for awhile. It still hurts that the magic still infuses the material, throbbing like a pulse. It’s not fair, but he clings to the feeling. On most days, it’s what makes him feel alive. Sometimes, when he’s desperate or the LV within him is making life unbearable, Sans curls his scarred fingers under the loop and gives it a deft tug.

It’s not the same.

* * *

Sans isn’t quite sure how many years pass, but he eventually creeps his way into the capital. Its streets are warm with the throng, the march of footsteps reverberating up his feet. It’s the most people he’s been around, but people tend to play a bit fairer in the capital, so he doesn’t necessarily worry, but nor does he drop his guard. It’s too close to the crown, too many laws and jurisdictions to fumble with than what’s worth the risk of public execution.

There’s enough people around that his normally suspicious Checks go unnoticed. It doesn’t prevent others from bumping shoulders with him, though. He’s got nasty scars over his orbits, hollow and empty since the injuries healed over. They must look intimidating at the very least, if Sans’ idle rubs over the chipped orbital plates is any indication to go by.

He’s heard of a new rank amongst the royal guard: a bloodhound, a term which makes the crook of Sans’ sharp teeth quirk. Over the years, he’s been yearning for a challenge. Breaking into the castle, bypassing the guards (he’s not stupid enough to kill them and alert the rest)… it’s been a fantasy he’s been indulging in his travels. It makes his magic curl at the edges, fire in his soul when the forge has been doused.

It’s an insane thought, but what else has he to lose?

He’s all too aware of eyes on him as he passes through the packed streets. There’s a crowd gathered but it’s hushed like at the gallows. Sans stands idly in place as some dignitary or whatever blathers on about something he doesn’t care about.

He feels a penetrating gaze on him, and his Checks glance off several people up the crowd to try to uncover just who it is. It falls flat when the speech is over and the self-appointed ‘important’ people retreat to whatever fancy shlubs they hide with. Sans finds it a little unnerving, like he was Checked, but then he wasn’t. There was no brush against his soul nor the feeling of the wind getting knocked out of him. He stands alone, suspicious.

He decides to lurk in wait for an opportunity to strike.

* * *

* * *

This is it. He’s had enough time. Sans skirts the keep, his footsteps light and slow. He’s removed most of his chains, hid them in a chamber when he’d first snuck in. He doesn’t expect to get them back. He doesn’t expect to leave alive.

It’s been four weeks since the strange presence in the capital’s city square and there have been no leads about the bloodhound. They’re an enigma, a brute at the king’s side. They say they follow him around like a lost puppy and unwaveringly obeys what the mad king orders.

Sans scowls at that, remembering the past. Remembering the way Papyrus was presented before him, as he was commanded to look at him as the Judge.

After a decade or more and the wound still feels fresh when Sans thinks about it. Absently, he rubs at his chest through his clothes, ignoring the way his soul throbs in protest. In order to kill the king, he’ll need to be swifter than his guard dog. Damn mutts never could keep their fat noses out of anyone’s business.

Sans’ mouth is dry as he draws in even breaths, staying quiet as he listens for footsteps in the distance. He’s partial to hard leathers when it comes to armour, though it’s not something he’s had the luxury of obtaining. He utilises speed for defense, and armour weighs him down. One hit and he’s dead anyway. From the static that comes back from his Checks, everyone in the castle is at LV 6 or higher.

The further into the keep he goes, the more the air is choked with dust, both monster and from time’s decay. He smells something, a waft of sour rot and it churns his magic. He’s used to the smell of vomit and festered wounds in the areas that he’s laid low in, but this really takes the cake. He mentally sniggers at his joke. He can feel a sharp pang of giddiness, evidence that he’s lost his goddamn mind.

When he hears the change of the guard, Sans slinks along the wall out of sight. He doesn’t hear the crackle of fire and it’s chilly where he is. There’s a light breeze, cold against his sweaty skull. Like touching a memento, he keeps a hand on his collar at the clasp, partially to make sure it doesn’t make a noise when he hears the scrape of metal and the jingle of chainmail.

Thank god for their ostentatious ceremony and bullshit. Without the schedule he’d overheard in one of the taverns last week, Sans wouldn’t have been able to set his plan into motion.

Unfortunately, dogs have a sharp sense of smell; he knew this already from his time with them in Snowdin, even before he went blind. Regretfully, as it reeks of cigarettes and old booze, Sans shifts off his leather jacket and most of his weight goes with it. He’ll be able to move all the more quickly without it. He’s not getting out of here alive anyway.

He hides the bundle under a window in the corner of the hall. He takes his lighter, his pack of cigarettes in case he has time for one last smoke before the rest of the guard gets into the throne room after he’s killed the king.

He wonders how it’ll go down. Admittedly, Sans didn’t think he’d get this far. It’s as though they’re not expecting anyone to actually try to assassinate the king, or they’re not concerned about it.

There’s a guard nearby. Their footsteps scrape and echo in the hall where Sans lurks in the shadows, poised to strike if need be. He could use a shortcut into the throne room, sure, but it would tip off the entire castle by pinpointing his location. Magic leaves a signature in the air and he just can’t take that gamble.

They’re approaching. If Sans focuses on his location from where he entered, to the mental map he has since working there, he can work this to his advantage.

He slips around the pillar two steps, flicking the knife out from his sleeve to his palm. He finds his mark as he swings upward, burying itself between the guard’s jaws. A wet warmth blossoms over his grip as the guard’s stuttered wheeze gargles out a cut off grunt, and Sans twists the blade to make sure they stay down.

He guides them away to his side of the pillar to dust quietly, listening if the coast is clear. LV burns in Sans’ head, ticking over from 8 to 9 in the span of a breath when the guard crumbles away to fine grit at his feet. He’s not so naïve as to believe that’s all there is. He’s not stupid.

The truth is as abrupt and clear as a strike to the head. Sans thinks for a moment that he sees something, a spark behind the hollows of his sockets where the lights of his eyes used to be. He didn’t hear anyone approach beyond the thrum of LV roaring in his skull. He didn’t hear footsteps, nor could he feel the weight of another’s life around him as he trudged along. His footsteps made no sound at all.

Things melt to pain and it all collects in his head as Sans sinks to the floor. God, he’s an idiot. There he goes. All for nothing. His HP takes a hit, down by 3 points. He sinks lower with a grunt, attempting to form an attack before the guard snuffs him out. It lands, but the magic crumbles away like silt just as Sans’ body gives out. It’s too much all at once, and the buzzing burn at his neck chips off another couple HP.

Sans wakes to the sound of laughter.

It’s not a hearty chortle. It’s low and vibrates in his chest, bruised from taking a few hits. It rises in volume the longer it goes on, unsettling as it blankets him with kindling dread. His mouth tastes like ash and his head is a groggy mess, making sense of the situation as soon as he’s regained consciousness.

It’s not his own laughter, that’s for damned sure. He knows the mirth of the mad king enough to know he’s been brought right to Asgore himself. He trains the look on his face to not look so pleased, but Sans can’t help it. Self-preservation has got him this far only to mock him.

Sans is dropped to the ground, a guard at each side of him. His ribs ache like one’s been snapped, but no, he’s whole. The back of his neck prickles like electric burns, his leg aches like a bitch. Fuckers must’ve tased him.

The mad laughter continues, echoing in the cavernous room, so loud it disturbs the dust from the stone pillars and beams above. Sans freezes when he feels the slam of LV from the opposite side of the room, immediately knowing to whom it belongs to.

LV 18, the mad king, the one Sans wants dead. He’s a spare 9 levels away from matching him, but he’s no boss monster. Asgore can fell him by flicking a toenail at him, as much as Sans wants to deny it.

The king’s mirth barks out. Sans can almost hear the froth of saliva, the flare of the boss monster’s red feral eyes. “Oh, this _is_ interesting!”

Sans’ grin tugs, but it’s not motivated by humour. He leans up on his arms and represses the grunt of pain lodged in his throat, rising in his chest like bile. Yeah, he broke something. He detects another presence next to the king - the hound, most likely. He attempts to glance a Check to gain his bearings, but the enquiry is slammed away with such a violent swing that it makes Sans’ head spin. It lands against the wall, sending values in a shockwave up the insides of his skull in a series of ones and zeroes. Apparently, Asgore doesn’t want any interference.

For a moment, he’s disorientated. Sans recalls the stench, the pain and the despair from a decade ago.

He pushes it aside, magic collecting in his joints. He constructs several attacks and thrusts them up from the floor, impaling the guards around him. They fall like they aren’t meant to keep him there at all. Like they’re disposable.

Rage seethes within his bones. It claws at him, tearing him apart just as much as the king’s laughter does. He wants to shut him up, he wants to carve that smile off his fucking _face-_

He dashes into the direction of the podium, rust red bone attacks peppering the tiles so he can use them as proximity beacons to know where he is. Sans knows the throne room like the back of his hand, he doesn’t need to see to know there are seven steps up to the dais. One of his attacks resonates as it plunges into the dusty violet carpeting.

Two bodies. One Asgore, the other the hound.

Four steps, three to the hound, the king is behind him.

He sends another flurry of bones down, turning the marble into rubble and setting off another reaction.

The hound’s moved.

The king speaks.

Sans keeps his hearing sharp despite the noise.

“--Edge-kill him!”

There’s hesitance, but the king’s guard flies forward. Edge’s footsteps are even but their breathing gasps out with Sans’ next attack. Fuck holding back, the guards are dead and there are only two left to take care of. He’s gotta make it quick, or Asgore might take it upon himself to join the fray. Sans knows that he’s so paranoid that he’d kill the both of them if he got the chance.

Sans can feel the rush of magic in the air, how it tingles on his breath, lights up in his body. He takes stock of the mental map he’s made of the area and shortcuts to another position, levying a swing just under the guard’s torso. It hits, shaves off thirty or so HP, KR burning at the wound, and he dodges the swing that comes down to meet with him.

His breath burns. As he brings up another attack, he lunges forward, blocking another attack. He’s at 4 HP, he can’t gamble like this. On the other hand, Edge’s attack doesn’t touch him.

Usually Sans has something to say. Usually he’ll spit any amount of vitriolic insults his enemies’ way, attack them with his tongue as well as his knives. He’ll chip away at them, bit by bloody bit, until the wind carries their dust into his nasal aperture.

But as he attacks, his legs slides down the grit of the ruined marble floors when Sans scrabbles back up to lunge himself back to his opponent. He starts to realise something with a bit more clarity, something that stuns him and catches him off guard.

They’re parrying.

They’re not attacking, not really. None of Edge’s attacks hit. He doesn’t take any damage. The guard, Edge, is controlling themself, but why?

To make a show? Is that all he was to these assholes!? Some goddamn fucking entertainment!?

Gritting his teeth, Sans hurls himself through another shortcut to land another blow, connecting with their leg. Then their shoulder. Then, he thinks, their jaw. Every time, they attempt to parry, but he’s wearing them down.

Who the fuck said this fucker was unbeatable!? They don’t know how to fight, or maybe Sans is just getting cocky. The king’s laughter dies down, replaced by something vehemently pleased, like it’s all just a game.

Sans starts to breathe hard. Between being ripped from consciousness and back again, and entering a Fight, he’s wobbly and unsure. The only reason that he hasn’t toppled over yet is because he doesn’t allow himself to. He’s running on pure magical adrenaline. Sans jolts from swing to bloody swing, chipping away at his opponent’s defences until, somehow, Edge drops their guard.

He wonders if he should’ve taken it. In the span of two seconds, he decides fuck it, go for broke, and he puts as much effort as he can muster into a stronger attack.

It’s just a larger bone, sharp at the tip, but it glides in easy, no give of flesh, no gurgle of blood. He aims for the soul, somewhere in their chest, hammering like a drum above the din of the fight.

Something snaps. Then there’s the scent of blood, of _marrow._ Sans feels something he’s come to forget, burning at the back of his brain as the gridline presents him with something he thought he’d never see again, never feel or brush or hold, to listen-

The way they gasp is tantamount to an injury years before, when Grillby nearly burned through Papyrus’ spine in an altercation. They don’t say a word. It has to be a trick, Sans thinks, panic overcoming him.

No, Papyrus would’ve come back to look for him if he was alive.

There has to be some kind of trick, he thinks as he grips the speared bone steadily eating away at the bloodhound’s HP.

40, 41, 42…

He wouldn’t do the king’s bidding, right?

43, 44-

“Is-” It’s the first word that drops out of his mouth, raw and too pained like the KR is burning at him instead. The magic is familiar, hot and burning with enough familiarity to knock Sans off his feet.

Meanwhile, the KR continues to burn in the wound like acid. Sans’ hand shakes as he goes to remove it, but the guardsman, _Papyrus_ _(his brother)_ , steps back, his breath on the verge of pain. Sans’ hand is slapped aside, a negligible swipe, but with its sting comes a small catch of healing.

Sans tries the Check again, so stunned that he’s nearly forgotten where he is. He feels Papyrus lunge towards him in the air and braces himself, crossing his arms over his face with a couple of bone constructs to block the attack.

> **[ * PAPYRUS 8 ATK 2 DEF  
>  ** *** It’s sure been awhile,  
>  ** **hasn’t it? ]**

Papyrus doesn’t say a word. When Sans parries the attack, the bones slide over steel, wrenching the guardsman away. He makes a sound low in his throat, unrestrained and too raw for his liking.

> **[ * 978 HP ]**

“Why-” _Why are you still here!?_

_Why didn’t you come back!?_

_Why didn’t you try to contact me?_

Sans swings again, the feelings and words trapped in his chest. He thrusts down hard and to his horror, the blow lands again. Papyrus knocks the flat of his sword against Sans’ ribs in retaliation, sending him back several feet. Then he grabs his arm. Sans can feel the prickle of magic around him and for a moment, panic settles over his soul.

_What if Papyrus is under the mad king’s influence?_

That can’t be right. He’s hallucinating, right? It’s just the new LV, picking at his brain, chipping away at his sanity much like the old king’s has. Papyrus’ values are too low to truly be him, and his HP too high despite how long they’ve been fighting. Sans does the mental gymnastics needed to focus on blocking the guardsman’s attacks to figure that… maybe… their HP was well over a thousand?

That’s not right.

Papyrus was only at LV 7. He’s not as reckless as Sans is. He wouldn’t succumb to the mad king’s desires, wouldn’t, he _wouldn’t-_

The next blow catches him in the shoulder, fuck, because he’s getting emotional. He’s doing the thing Papyrus warned him for, what he’d taught his brother against for all these years. It hurts like a bitch, but it’s steel on bone, and it bruises and sends Sans down to one knee.

Gritting his teeth, Sans dares to taste the name in his mouth, his voice raw and pinched from years of under use. He’s biting back the name as much as the emotion straining him. _“Papyrus.”_

There’s a break. He hears a scoff from Asgore, seated on his throne several feet away. Then a mild chuckle, like it’s amusing.

He Checks again, and Papyrus’ values are the same, less some HP. It strangles him, cutting him down to his cracked soul.

Papyrus doesn’t want to fight him.

He’s parrying and swinging, but there’s no heart in the moves. He’s got no desire to hurt him, and Sans feels it like a blow to the chest. He doesn’t know how to process it all, but it’s certainly not one of his penchants for demanding answers in front of his enemies like some Saturday morning drama piece.

His chest feels tight, though. Like it might split.

He can’t cry.

Hasn’t cried in forever. But he feels the heat in his skull, obscuring the static he detects like a blanket. He doesn’t want to fight Papyrus either.

He lets the next strike hit him. It still hurts, but it doesn’t touch his HP. Of course it doesn’t. Papyrus doesn’t want to harm him. Not really. It’s a show. What he gets for his lack of efforts is Papyrus’ footsteps approaching, his plate armour making him sound ridiculous. With the thought, Sans’ grin upturns just a little, reminiscent and wistful.

“Fuck right it’s been awhile,” he says lowly, his voice an unnatural gravel.

Papyrus hooks his hand into the crook of Sans’ elbow, locking him against him and pulling him up. Sans’ body burns with protest and his joints ache just as bad to make it look like a struggle, but when he holds on, Sans detects that one of his attacks is still wedged into Papyrus’ ribs.

Papyrus makes a bitten off noise like he got punched, but he doesn’t retaliate. Instead, he pulls Sans close to his body and Sans can feel the thrum of magic, alive and hot, surrounding them.

There’s a summoning around them, a graveyard of bones that’s built up every time Sans attacked and fell back. Papyrus conjured one every time he struck, but never dispelled it. His breaths are a little harsh, but Sans can hear the familiar propriety and curt gauntness in Papyrus’ voice like a lost dream.

It’s a whisper, normally one he hates. Normally one he launches back with distaste and a scoff. Sans finds he’s missed it too much.

“Between eight and ten,” his brother murmurs, all cold calculating behind a layer of sweet, sweet relief, “give it all you’ve got.”

A grin touches Sans’ teeth, wide and sharp. He didn’t think he had it in him to feel that way anymore, the blithe way he shrugs like it’s the same orders from yesteryear. He laughs his old familiar half-laugh, grimacing just a tad when he shrugs that infernally noncommittal way of his.

“Heh, you’re the boss.”

He feels the gentle prickle between bursts, but when Papyrus turns, Sans pressed against his side, Sans knows exactly where to aim. The dais is fourteen and an eighth feet away, five feet from the ground in height, and Sans launches everything he has in that direction. He calls upon blasters even though they make him sick, he hurls every bit of magic he can muster.

Most of all, he pours his hate, his fury, in every last attack. He only does pitiful amounts of damage, but Sans’ tongue bleeds with how hard he bites it in concentration. He feels pathetic, but he feels stronger, held against Papyrus’ side ~~_protectively_~~ like he’ll get in the way if he moves.

And Papyrus is throwing out all he has too. Sans can’t Check right now, he’s too focused on pummelling Asgore to dust like it’s all he lives for now, but he would’ve seen Papyrus’ values shoot up as the desire to fight strengthens within him.

He’d never say it out loud, but his brother is pretty cool.

They push themselves until they have nothing left. Papyrus sinks to the floor, keeping Sans pressed against his side like he’s staunching a wound. Sans’ joints feel so weak he’s at risk of crashing. His reserves are so watery thin. They’re both gasping in the dusty hall, a tentative hope between them that this is it. It’s over.

Sans’ gasps are harsher than Papyrus’, though Papyrus has more strength, he lets his arm loosen from around his brother’s arm. Relief bleeds from Papyrus, heavy as a wound, and he leans against Sans to figure out if he’s really there or not. Sans scrabbles to hold him, wanting much of the same.

They can’t stay, no matter how worn out they are. It’s only a matter of time before someone comes to inspect the noise, and even though Asgore was a tyrant, his sympathisers are everywhere. They’re sitting ducks here, and Sans knows it.

There’s a buzzing in his skull, though Sans doesn’t know if it’s because of the magic ringing in the air, the sound echoing all over the castle, or because, for one alarming moment, he _feels_ Asgore behind them.

Papyrus freezes, because of course he fucking does. He’s exhausted himself to the point where he stares at the beaten sovereign, trident in hand. Sans can practically taste the fear sweat in the air.

Sans can push himself. He’s done it before. He’ll hate himself in the morning for it, if he survives, but anything to protect his brother. He’d lost him once and he’s not going to do it again.

Even though the heavy stink of rot and sick wafts from the boss monster, Sans springs up between his brother and the monarch, one of both his and Papyrus’ bone constructs tight in his fist. They weld together, magics mingling, and his grip splinters it as he drives it up under Asgore’s ribs.

He doesn’t want to gain the EXP for killing a LV 18 monster. Not alone. Papyrus has had to suffer, it’s only fair.

Sans can taste the vengeance as blood ripples down the lengths of his arms, and Asgore’s body shudders. It’s a cheap shot, but Sans is tired of fighting. He wants it done, to grit Asgore’s dust into the floor with his boot.

He gives the bone a twist and a good shove, his bones prickling along his neck and back when the king releases a strangled plea. Sans ignores the words as though he’s lost his sense of hearing as well, and he negligibly pushes the giant monster’s body away as he starts to crumble. Dust smears along with brackish blood, coating his clothes and making the floor slick.

It’s done.

Asgore falls to dust, and Sans, stunned and alive, drops, all the energy bled out of him. He still clings to a thread of consciousness though, blindly fumbling for Papyrus’ shoulder. His soul wrenches when he finds another one of his bone attacks lodged in, and his Check pings off Papyrus’ remaining 332 HP as he tears it out.

Papyrus hisses, but he’s alive.

They’re both alive, and the king is dead, and they’re goddamn criminals as well as royal executioners. Well, they’ve never been saints. Sans grabs a hold of the familiar fabric of Papyrus’ scarf, wrapped tightly around his throat, he bends down, his breaths shaking as it all weighs down on them at once.

He’ll fight anyone to say the gesture he gives his brother as ‘fond’. He headbutts him, enough to hurt, but not as much as he’d usually do in the past. His chest is still tight and the EXP is still racking up between them. Papyrus has already ticked over to LV 12.

Carefully, since he doesn’t want to be misinterpreted, Sans speaks, his false throat hoarse and his breaths stuttered in pain. “How the hell you survived without me,” his voice doesn’t fucking break, “is a fucking miracle.”

“I grieved for you,” his brother murmurs, pained.

Sans swallows away the frailty in his voice, his fingers seeking the outlines of his brother’s face to make sure it’s really, _truly_ him. He nods, his false throat trying to strangle him when he realises that _yes, it’s him._

“You broke my ribs,” Papyrus huffs, not sounding particularly offended.

Sans’ nuzzle is more of a headbutt and he nods again, the wounds freshly open, their sore skulls slotting together as they’d always meant to be. Papyrus makes a difficult grunt below him, half propped on one elbow to pull Sans close. It’s too tender than what they were ever used to. Sans stiffens as though the embrace has knives buried in it, but he eases just a fraction.

“I was aiming for your soul, so guess I’m rusty after all this time,” Sans retorts after a moment of bone-chilling silence. “Good thing, huh.”

Papyrus gives him a rough shove, but doesn’t actually push him away. A slight smirk breaks out on Sans’ face, hesitance poured into fragile hope. After all, he’s tired, and if Papyrus holds onto him, he can teleport them away to safety and no one will be the wiser.

**Notes for the Chapter:**

> **Content warning(s):** vomiting, reference to past eye trauma, violence, thoughts of regicide, incestuous feelings, grief, mental health issues, a whole lotta murder, blood & gore mention.
> 
> WEW.  
> (I will probably write up an epilogue of sorts but it won't be immediately ♥)


End file.
